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Biomass and Bioenergy 31 (2007) 497–502

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Genetic variability and divergence studies in seed traits and oil contentof Jatropha (Jatropha curcas L.) accessions

N. Kaushika,�, Krishan Kumara, Sushil Kumara, Nutan Kaushikb, S. Royb

aCCS HAU, Regional Research Station, Bawal (Rewari) 123 501, IndiabThe Energy Resource Institute, New Delhi 110001, India

Received 13 December 2006; received in revised form 10 January 2007; accepted 11 January 2007

Available online 13 March 2007

Abstract

Variability in seed traits and oil content of 24 accessions of Jatropha curcas collected from different agroclimatic zones of Haryana

state, India were assessed. There were significant differences (Po0.05) in seed size, 100-seed weight and oil content between accessions.

Maximum seed weight was recorded in seeds collected from IC-520602 and the least weight was recorded in IC-520587. Oil variability

ranged from 28.00% in IC-520589 to 38.80% in IC-520601. In general phenotypic coefficient of variation was higher than the genotypic

coefficient of variation indicating the predominant role of environment. High heritability and genetic gain were recorded for oil content

(99.00% and 18.90%) and seed weight (96.00% and 18.00%), respectively, indicating the additive gene action. Seed weight had positive

correlation with seed length, breadth, thickness and oil content. On the basis of non-hierarchical Euclidian cluster analysis, six clusters

were obtained with highest number of accession falling under cluster III. Maximum and minimum intra cluster distance was observed for

cluster VI (2.499) and for cluster III (2.252), respectively. Whereas maximum inter-cluster distance was observed between cluster VI and

IV (5.129) and minimum between cluster III and II (2.472). Among the six clusters formed cluster IV showed maximum cluster value for

seed size whereas, cluster VI showed maximum value for oil content and seed weight. Thus on the basis of present finding it is suggested

that the crossing between accessions of cluster IV and VI will result in wide spectrum of variability in subsequent generations.

r 2007 Published by Elsevier Ltd.

Keywords: Jatropha curcas; Oil content; Phenotypic coefficient of variation; Genotypic coefficient of variation; Heritability; Genetic gain; Genetic

divergence; Euclidian cluster analysis

1. Introduction

For initiating rational tree-breeding programmes,knowledge of genetic variability of concerned species isnecessary, as it affects not only the composition of groupvariation but also evolutionary potentialities of the groupconcerned. Introduction and evaluation of provenanceprogenies is an essential aspect in agroforestry research[1–3]. Considerable genetic variation in growth, chemicalcomposition of seed and seed traits at the level ofprovenance, variety or progeny can be expected particu-larly in out-crossing species such as many species ofAlbizia, Jatropha, Acacia and Prosopis, which are widelyused in agroforestry systems throughout the worldwide

e front matter r 2007 Published by Elsevier Ltd.

ombioe.2007.01.021

ing author. Tel./fax: +91 1284 260507.

ess: nk20025@rediffmail.com (N. Kaushik).

landscapes. The variation would be useful as a source offuture genetic selection provided the desired ideo types foragroforestry systems are clearly defined [4–6]. Bold andheavy seeds enable the seedling to grow vigorously [7] andwith better seedling vigour will ensure lesser nurserymanagement time thereby lessening the maintenance cost.Genetic variation in seed morphology and oil content ofJatropha can be of great potential in tree improvementprogrammes, particularly selection of genotypes havingmore oil content and yield.

Jatropha curcas L. is a multipurpose species with manyattributes and considerable potential. The oil from the seedis potentially the most valuable end product. Nearly 40%of the land area in India is wasteland. However, a largenumber of latex-bearing and oil-yielding plants can growunder such unfavourable agroclimatic conditions [8,9].J. curcas, a member of Euphorbiaceae can grow well under

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such adverse climatic conditions because of its lowmoisture demands, fertility requirements, and toleranceto high temperatures. It is found throughout most of thetropics and known by nearly 200 names, which indicate itssignificance. In the recent past, the economic importance ofJatropha has been increasing because of the use of its oil asa fuel (diesel) substitute. Jatropha is a little known herbaldrug of Unani medicines. It is a potential source of herbaldrug in dental complaints [10]. The milky sap of J. curcas isused in Mesoamerica for the treatment of differentdermato-mucosal diseases [11]. Extracts from the plantare known for their medicinal properties and their effectson a wide array of organisms including insect pests,molluses and nematodes [12–16]. It is truly a multipurposetree species fit for agroforestry and other afforestationprogrammes.

Little work has been done so far on germplasmcollection and its evaluation for chemical composition(oil content) of seeds of India’s arid and semi-arid species,however; Ginwal reported seed source variability ofJ. curcas in central India [17]. The objective of the presentstudy was to study the variation in seed traits and oilcontent in 24 accessions collected from Haryana state ofIndia.

2. Material and methods

An extensive survey was conducted to select thecandidate plus trees (CPTs) of Jatropha from different

Table 1

Seed size and oil content variability in Jatropha curcas

CPT Accession No. (IC No.) Seed length (mm) Seed breadth

1 IC-520586 16.82 10.53

2 IC-520587 16.49 10.24

3 IC-520588 16.31 10.16

4 IC-520589 17.04 10.61

5 IC-520590 17.25 10.78

6 IC-520591 16.63 10.45

7 IC-520592 16.33 10.55

8 IC-520593 16.83 10.61

9 IC-520594 16.61 10.88

10 IC-520595 17.63 10.53

11 IC-520596 16.90 10.63

12 IC-520597 16.31 10.18

13 IC-520598 16.12 10.76

14 IC-520599 16.69 10.92

15 IC-520600 17.39 10.92

16 IC-520601 16.33 10.49

17 IC-520602 17.30 10.72

18 IC-520603 16.40 10.45

19 IC-520604 16.63 10.63

20 IC-520605 17.08 10.90

21 IC-520606 16.00 10.33

22 IC-520607 16.45 10.31

23 IC-520608 17.27 10.92

24 IC-520609 16.76 10.75

SEm (7) 0.14 0.11

CD at 5% 0.37 0.30

locations of Haryana. The selection was made onphenotypic assessment of characters of economic interesti.e., yield potential, number of capsules per cluster,crown spread, girth, disease resistance etc. A total of 24CPTs (morphologically superior trees) were selectedfrom latitude ranging 281010–291780N and longitude751270–771050E. The morphological observations of theselected trees were recorded. The total height of thestanding tree was recorded with the help of Ravi’sMultimetre, employed for this purpose. Basal girth wasrecorded with the help of measuring tape. Crown spreadwas also recorded.From each CPT mature capsules were collected during

December 2004. One kilogram seed was collected fromeach CPT to provide potentially useful genetic variation.Seeds from capsules were extracted through manualthreshing. The seeds were further cleaned through winnow-ing. Thus seeds collected from 24 CPTs were submitted toNational Bureau of Plant Genetic Resources, New Delhifor IC numbers from 520589 to 520609 (Table 1). The seedswere separated from the fruit which is moist, cleaned andstored in muslin bags at ambient conditions. All seed lotswere dried under similar temperature and humidityconditions to reach a constant weight. Five samples weredrawn from each seed lot and 100 random undamagedseeds (total 500 seeds) were measured for their length,width and thickness in millimeters. For seed weight fivesamples of seeds including 100 seeds each, were taken fromeach seed lot and measured for weight and expressed in

(mm) Seed thickness (mm) 100-seed weight (g) Oil content (%)

7.79 52.50 30.91

7.51 49.20 30.95

7.53 52.50 30.74

8.00 62.90 28.00

7.84 64.50 32.53

7.74 55.40 32.43

7.77 63.30 32.53

7.79 62.50 31.50

7.86 60.00 33.48

7.90 59.40 28.77

7.86 64.90 34.50

7.41 59.80 33.42

7.45 57.10 37.96

7.92 57.50 38.31

7.92 64.70 31.91

7.96 66.50 38.80

8.33 69.20 34.17

7.95 66.33 34.02

7.86 63.70 32.27

8.04 57.70 33.02

7.24 64.90 38.18

7.57 54.80 34.85

7.67 51.20 32.53

7.65 59.90 29.26

0.12 0.67 0.73

0.32 1.90 2.00

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Table 3

Genotypic (G) and Phenotypic (P) correlation coefficient between seed

and oil traits in Jatropha curcas

Characters Seed

length

Seed

breadth

Seed

thickness

Seed

weight

Oil

content

Seed length G 0.544** 0.687** 0.103 �0.535**

P 0.566** 0.570** 0.102 �0.469**

Seed breadth G 0.587** 0.221* 0.074

P 0.461** 0.170 0.056

Seed thickness G 0.521** �0.168

P 0.398* �0.124

Seed weight G 0.235*

P 0.230*

** significant at 1% level.

* significant at 5% level.

N. Kaushik et al. / Biomass and Bioenergy 31 (2007) 497–502 499

grams. The oil content of seeds was estimated by soxhletmethod using three replicates for each seed lot.

Analysis of variance was carried out following theprocedure given by Panse and Sukhatme [18]. Thevariability, heritability in broad sense, genetic advance aspercent of mean, phenotypic and genotypic variance,phenotypic coefficient of variation (PCV) and genotypiccoefficient of variation (GCV) were worked out for seedand oil content traits as suggested by different workers[19–21]. The genetic divergence was calculated by usingnon-hierarchical Euclidian cluster analysis [22].

3. Results

3.1. Seed size

Significant differences (Po0.05) occurred among theaccessions for seed size (Table 1). Maximum seed length(17.63mm) was observed in IC-520595 followed byIC-520600. Minimum seed length (16.00mm) was recordedin IC-520606 followed by IC-520598. The low-rankingaccessions differed significantly from rest of the accessionsexcept IC-520588, 520597 and 520598. Seed breadth variedfrom 10.16–10.92mm with maximum breadth in IC-520599, 520600 and 520608 followed by IC-520605. Therange for seed thickness varied from 7.24mm in IC-520506to 8.33mm in IC-520602.

3.2. Seed weight and oil content

The 24 accessions showed significant variability for 100seed weight and oil content. For 100 seed weight (69.20 g)the top ranking accession was IC-520602 closely followedby IC-520601 and 520603. The top ranking accessionsdiffered significantly with all the remaining accessions.Minimum 100 seed weight (49.20 g) was recorded inIC-520587. Oil content variability was also recordedamong the different accessions. It varied from 28.00% inIC-520589 to 38.80% in IC-520601.

3.3. Genetic variability and association studies

The amount of genetic variation expressed by differentseed and oil traits could be judged through the study

Table 2

Estimation of genetic variables for seed and oil traits in Jatropha curcas

Traits Variance Coefficient of

Genotypic Phenotypic Genotypic

Seed length 0.17 0.22 2.45

Seed breadth 0.05 0.08 2.00

Seed thickness 0.04 0.08 2.71

Seed weight 28.76 30.10 8.94

Oil content 8.56 8.56 8.83

of PCV and GCV. Variance components for varioustraits are presented in Table 2. The magnitude of PCVwas higher than the corresponding genotypic ones for allcharacters. Seed weight registered highest GCV (8.94%)and PCV (9.14%) followed by oil content. Heritabilityestimates in broad sense were higher than 54% understudy, which reflected the predominance of heritablevariation for all the traits. The highest heritability of99.00% was recorded for oil content closely followed byseed weight. The genetic advance as per cent of meanranged from 3.10% for seed breadth to 18.19% for oilcontent (Table 2).Seed length was significantly and positively correlated

with seed breadth and seed thickness at both phenotypicand genotypic levels (Table 3). Seed length showed negativebut significant correlation with oil content. Seed breadthalso showed positive correlation with all the traits. Positiveand significant association was observed between seedweight and oil content.

3.4. Divergence studies

On the basis of non-hierarchical Euclidian clusteranalysis, 24 accessions were grouped in to 6 clusters(Table 4). The maximum number of 6 accessions wasincluded in cluster III followed by cluster IV (5 accessions),whereas cluster VI included only 2 accessions. The clusterpattern proved that geographical diversity need notnecessarily be related to genetic diversity.

variation (%) Heritability (broad

sense)

Genetic advance as

% of meanPhenotypic

2.79 77.0 4.42

2.66 57.0 3.10

3.68 54.0 4.10

9.14 96.0 18.00

8.83 99.0 18.19

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Table 5

Estimates of inter- and intra-cluster distances for seed and oil traits in

Jatropha curcas accessions

Clusters I II III IV V VI

I 2.042 2.568 2.824 3.034 2.860 4.005

II 1.770 2.472 2.855 3.969 3.920

III 1.707 2.829 3.265 3.374

IV 2.252 4.468 5.129

V 1.644 3.286

VI 2.499

Table 6

Cluster mean value for seed and oil traits in Jatropha curcas accessions

Clusters Seed

length

Seed

breadth

Seed

thickness

Seed

weight

Oil

content

I 16.87 10.66 7.71 54.75 31.28

II 16.79 10.90 7.94 58.40 34.94

III 16.57 10.56 7.86 64.54 33.94

IV 17.32 10.71 8.00 64.14 31.08

V 16.39 10.22 7.51 54.08 32.49

VI 16.06 10.55 7.34 61.00 38.07

Table 4

Composition of Euclidean clusters for seed and oil traits in Jatropha

curcas accessions

Cluster No. of accessions Accessions (IC numbers)

I 4 520586, 520591, 520609, 520608

II 3 520594, 520605, 520599

III 6 520592, 520603, 520593, 520604,

520596, 520601

IV 5 520589, 520595, 520590, 520600,

520602

V 4 520587, 520588, 520597, 520607

VI 2 520598, 520606

N. Kaushik et al. / Biomass and Bioenergy 31 (2007) 497–502500

The inter- and intra-cluster distances are presented inTable 5. The intra-cluster distances ranged from 1.644 to2.499 with maximum value in cluster VI followed by clusterIV and cluster I. Minimum intra-cluster distance was foundin cluster V. The highest inter-cluster distance was foundbetween cluster VI and V (5.129) followed by cluster V andIV (4.468). The minimum inter-cluster distance wasobserved between cluster III and II (2.472).

Cluster means indicated significant variation amongclusters particularly for oil content and seed weight. As isevident from Table 6, cluster VI recorded maximum oilcontent and seed weight, while cluster IV recordedmaximum length, thickness and seed weight. Thus it maybe suggested that crosses involving under cluster VI and IVmay result in substantial segregates and further selectionfor overall improvement of species.

4. Discussion

The study of seed morphological characters of thenatural populations is often considered to be useful stepin the study of the genetic variability. Significant (Po0.05)variation was recorded for seed length, breadth and 100-seed weight. Variation in J. curcas seed sources with respectto their morphological characters could be due to fact thatthe species grows over a wide range of rainfall, temperatureand soil type. Such variations in relation to habitat havealso been reported in a number of tree species. Variousecotypes/provenances/seed sources of J. curcas exhibitvariation in seed morphological traits [7,17,23]. Similar

variation has also been reported in Azadirachta indica

[24–26], Acacia nilotica [27], and Acacia catechu [28].Therefore, some of the basic material (seed) from those

provenances/trees having more seed weight and oil contentmay be used for further improvement programme, sincethe improvement in germination and seedling growththrough seed size manipulation has been reported in caseof Hardwickia binnata [29], H. binnata and Cholosphosper-

mum mopane [30] and J. curcas [7].Little difference between PCV and GCV and high

estimates of heritability (broad sense) for all charactersunder study revealed the heritable nature of variabilitypresent. High estimates of heritability (454%) have alsoenvisaged that environment has comparatively low influ-ence for the seed traits and oil content. Estimates of geneticadvance as percent of mean ranging from 3.10% for seedbreadth to 18.19% for oil content further suggested thepotentiality of the test material for future improvementthrough selection. Heritability has an important place intree breeding as it provides an index of the relative role ofheredity and environment in the expression of varioustraits. Dorman [31] reported that heritability estimate isimportant in tree improvement programmme. It is alsouseful for ranking importance of each trait in cross-breeding programmes. Gains from tree breeding pro-grammes depend on the type and extent of geneticvariability. The best gains are for characteristics that arestrongly under genetic control and have a wide range ofvariability [32]. High heritability accompanied by highgenetic advance for growth parameters have been reportedby Solanki in Prosopis cineraria [33]. Gera also reportedhigh heritability in teak for height (85.50%) and collardiameter (74.02%) [34].Genotypic and phenotypic correlation coefficients be-

tween various characters under study revealed thatmagnitude of correlation coefficient at genotypic levelwas higher than their corresponding phenotypic coefficientof correlations. This clearly indicated the genotypicassociation among the characters. The correlation matrixrevealed that statistically significant correlation of seedweight existed with oil content, seed length, breadth andthickness, therefore, seed weight can be considered asimportant trait for early selection of seed sources. Similarfindings between seed size and weight have been reported inA. indica [24,26] and A. catechu [28]. The consideration of

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seed weight in delineating and understanding the geogra-phical variation has been advocated because of the leastplasticity of this character [35]. Seed length was alsofound positively correlated with seed breadth. Similarfindings were also reported by Ramchandra [36] andKumar et al. [28].

The D2 statistic, which is based on several characters, isone of the powerful tools to assess the relative contributionof different component traits to the total diversity toquantify the degree of divergence between population tounderstand the trend of evolution and choose geneticallydiverse parents for obtaining desirable recombination. Theclustering pattern in this study revealed that trees fromdifferent geographic regions were grouped together in acluster and vice-versa suggested that geographical diversitydid not necessarily represent genetic diversity. This was inline with results obtained earlier through D2 analysis bySaini et al. [37] and Kaushik [38]. The trees that originatedin one region had been distributed into different clustersindicated that trees with same geographic origin could haveundergone change for different characters under selection.

Maximum intra-cluster distance (2.499) shown by clusterVI is an indicator of selection of parents for hybridizationwithin the cluster. The maximum inter-cluster distance(5.129) between cluster VI and V followed by cluster V andIV (4.468) indicating wider genetic diversity between thetrees in these groups and selection of parents from suchcluster for hybridization programmes would help toachieve novel hybrids. The minimum inter-cluster distanceindicated that trees in these clusters were of close relation-ship. Hence, selection of parents from these two clusters isto be avoided. Theoretically speaking, the clusters, whichare having more, inter-cluster distance and high meanvalue would produce divergent trees. Therefore, those treesshould be selected which are having high inter-clusterdistance. Cluster VI and cluster V are having high inter-cluster distance. So, the trees belonging to these clusterscould be selected as parents for breeding programme.

This kind of study can help to identify the bettergenotypes of J. curcas having better yield and oil content.Therefore, the best genotypes selected will improve thepoor sites for agroforestry systems and energy plantationsin the wastelands.

Acknowledgement

The financial support to conduct this experimentprovided by the National Oil seed and Vegetable OilDevelopment Board, Gurgaon, Ministry of AgricultureGovernment of India is fully acknowledged.

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